Cross-arm support for safety coils



Jan. 14, 1930. J. J. THOMASON ET AL 1,743,168

CROSS ARM SUPPORT FOR SAFETY COILS Filed March '7, 1927 WITNESSES: Jase 2VENTORQ$JM Lee .h/a ahlffl'an' and George P 05 ATTORNEY Patented Jan. 14, 1930 UNITED STATES J'OSEPE J. THOMASON, LEE 8. WASHINGTON, AND GEORGE P.

PATENT OFFICE MAY, 01' 8'1. LOUIS, HIS- A CORPORATION 01 PENNSYLVANIA CROSS-ABM SUPPORT FOR SAFETY COILS Application filed larch 7, 1927. Serial No. 173,834.

Our invention relates to devices used in connection with line material for the transmission ofelectrical energy, and more particularly to a device for mounting instruments and transmission line material on poles or other supports.

Most of the street-lighting systems now in use utilize a one-wire series line for the transmission of the electrical energy used in furnishing current to the lamps of the lighting units.

The voltage carried by the series lines is high, and it is considered dangerous to bring leads from these lines directly to the lighting unit. Consequently, a transformer is provided, the secondary voltage of which is compartively low, and the leads from the secondary winding are connected to the lighting b unit.

One of the objects of our invention, therefore, is to provide a simple but effective means for mounting the safety coil or transformer on a transmission pole.

Another object of our invention is to provide a mountingof the above character provided with insulated terminal supports such that the transformer terminals may be connected to the transmission lines or conductors and the leads to the lighting unit without crossing one another or touching the metal parts of the support.

Another object of our invention is to provide a mounting such that the opposing strains caused by the weight of the two wires of the transmission line are balanced, one against the other, and that all other connecting members hang loosely, whereby the unbalanced strains on the cross-arm are reduced to a minimum.

A still further object of our invention is to provide a device of the above character which shall be simple and rugged in construction and economical to manufacture.

Our invention may be better understood by reference to the accompanying drawings, in which like reference numerals indicate like parts.

Fig. 1 is a view in side elevation of a mounting constructed in accordance with our invention, showing the transformer in place.

together with the leads and wires used in making connections;

ig. 2 is a view in end elevation of the mopnting and transformer shown in Fig. 1; an

Fig. 3 is a view in cross-section taken along the llne III-III of Fig. 1.

Referring to Fig. 1 a cross-arm or s reader arm 1 is bolted to a transmission 0 e 2 by means of bolts 3 and is made rigid y means of a tie rod 4 in the conventional manner wel1-known in the art.

Our support is a T-shaped member 7 comprising an upper body member 8, I-shaped in cross section, supported by a stand or pedestal 9. Laterally-extending webs 12 and 13 are provided to furnish greater rigidity etween the supporting stand and the body member. A stud bolt 14 is screwed into a tapped opening 15 in the supporting stand 9. and the support is fastened to the cross arm 1 by inserting the stud 14 downwardly through a suitably prepared opening 16 in the cross arm' bolting the support down by means of a nut 17. A shoulder 21 of the supporting stand 9 and the stud bolt 14 furnish a sufiiciently rigid mounting.

The upper surface 22 of the body member 8 is flat and provides a seat for a metal container 23 holding a suitable transformer or safety coil (not shown). The metal container or safety coil box 23 is provided with two lugs 24 and 25 on its lower edges. These lugs and openings 26 and 27 in the body member are arranged to coincide so that the safety coil box may be fastened to the supporting member by means of, vertically extending bolts 31 and 32. v

The safety coil is provided with two primary or high-tension leads 33 and 34, and two secondary or low-tension leads 35 and 36. These leads are electrically insulated from the safety coil box by the bushing type insulators 37, 38, 39 and 40, respectively.

The supporting member 8 is formed into an L-shaped branch at each end, as shown in Figures 2 and 3. The vertical portions of the branches constitute insulator pins 41 and 42 on which are mounted suit-able high-tension insulators 43 and 44. The axes of the other portions of each branch are perpendicular to the axes of the first named or vertical portions and they are preferably perpendicular to the axes of the supporting member 8. The latter portions constitute insulator pins 15 and 46, on which are mounted suitable lowtension insulators 47 and 48. In order to decrease the weight of the supporting member. the insulator pins may be made hollow, as shown in Fig. 3. v

The high-tension wires .)1 and 52 are fastened to and terminate at the respective high tension insulators in the usual manner. The low-tension leads 53 and 5, are fastened to the respective low-tension insulators in a like manner.

The transformer leads 33, 34, 35 and 36 cannot be anchored to the safety coil box and for this reason the leads will not Withstand anv considerable pull. Therefore. in connecting the primary leads 33 and 34 to the high tension wires 51 and 52, respectively, and the secondary leads and 36 to the low-ten sion wires 53 and 54;. respectively, sufiicient slack must be allowed, as illustrated. so that the safety coil leads will not be subjected to strain.

In practice, our support is mounted on the cross arm, as has been explained. Fig. 2 shows the position of the low-tension insulator 47 and pin 45 with relation to the pole when the lighting unit and the line conductors are on the same side of the pole. If desired, the support may be reversed so that the low-tension insulators will be between the support and the pole. This modified arrangement may become necessary if the lighting unit is to be placed on the opposite side of the pole from the safety coil.

The weight of the high-tension wires 51 and 52 between successive poles of the transmission line necessarily creates considerable pull on the high tension insulators used in supporting the line. Our device makes ample provision for the strain incident to this pull by utilizing a one piece cast supporting member. The pull of the wire 51 is trans mitted through the insulator pin 41 and the supporting member 8 and is balanced by the pull of wire 52 transmitted to the supporting member through pin 42. Consequently,

as these two pulls are balanced against each other in a straight line, the cross-arm support is subjected to the minimum of torsionat or horizontal shearing strains.

Our invention eliminates pull on the transformer leads and properly distributes the strains from the transmission lines throughout the support. The device is so arranged that the leads will not cross each other, nor are they allowed to come in contact with any metal part.

Although we have described a specific form of our device and have described it in connection with a specific kind of transformer,

the device may be readily modified for mounting various instruments and transformers on poles and for purposes other than the one described. \Ve desire it to be understood, therefore, that such modifications may be made without departing from the spirit and scope of our invention as defined in the appended claims.

We claim as our invention:

1. The combination with -atransmission line support, of a device for electrically connecting a branch line to the transmission line, and a unitary structure comprising a T- shaped support for said device having insulator mountings on the ends thereof.

. 2. The combination with a transmission line support, of a device for electrically connecting a branch line to the transmission line, and a unitary structure comprising a T- shaped support for said device, means for fas-- tening the device on the upper surface of the support and two vertical and two horizontal insulators mounted on the ends of said support.

3. In combination, in a transmission-linestructure, a main support, a translating device mounted thereon, an insulator mounted on said support independently of said device for supporting one end and assuming the mechanical load, of a line section, a second insulator mounted on said support independently of said device for supporting one end of a branch-line conductor, and a slack lead connected between each of said ends and said device.

4. In combination, in a transmission-line structure, a main support, a translating device mounted thereon, a single means for sup porting a plurality of insulators independently of said device, one of said insulators being for supporting one end of a line section and another of said insulators being for supporting a branch-line conductor, and leads extending from said device to said line section and to said branch-line conductor.

5. In combination, in a transmission-line structure, a ground support, a cross-arm thereon and means on said cross-arm including a supporting element, an insulator and an electrical device, said insulator and device being freely spaced apart in the direction of the line and separately mounted on said element, a conductor supported by said insulator having a main section extending away from the structure and a slack section between the insulator and the device.

6. In combination, in a transmission-line structure, a ground support, a cross-arm thereon and means on said cross-arm includ ing a supporting element, an insulator pin, a pair of insulators and an electrical device, said pin and device being separately mounted in freely spaced relation to each other on said element, and said insulators being mounted on said pin for supporting main conductor sections extending away from the structure and slack conductor sections between the insulators and said device.

7. In combination, in a transmission-line structure, a ground support and means on said support including a supporting element, an insulator pin having angularly-related arms, a plurality of insulators disposed one on each of said arms and an electrical device, said pin and device being disposed in spaced relation on said element, and conductors extending between the device and the insulators and beyond the insulators. a

8. A transmission-line structure comprising a main-base support, a secondary supporting unit thereon, a tertiary insulator support on said unit, an insulator on said insulator support and an electrical device mounted on said unit free of mechanical support by said insulator support and electrically associated with said insulator.

9. In combination, a transmission-line pole, a cross-arm thereon transverse to the line, a support on the arm in the direction of the line, insulator mounting elements spaced relative to each other along the support, a plurality of insulators on each of said elements and an electrical device on the support between said elements and free of mechanical support thereby.

10. In combination, a transmission-line pole, a cross-arm thereon transverse to the line, a support on the arm in the direction of the line, insulator elements spaced relative to each other along the support, and an electrical device on the support between said ele- Lnents and free of mechanical support there- 1 1. In combination, a main transmissionline mounting structure, a single integral auxiliary support thereon, a translating device'mounted on said auxiliary support, an insulator mounted on said auxiliary support independently of said device for supporting one end, and assuming the mechanical load, of a line section, and a slack lead connected between said end and said device.

In testimony whereof, we have hereunto subscribed our names this twenty-fifth day of February, 1927.

JOSEPH J. THOMASON. LEE S. WASHINGTON. GEORGE P. MAY. 

